Page 144 - Color_Atlas_of_Physiology_5th_Ed._-_A._Despopoulos_2003

A. O 2 supply: Krogh’s cylinder model
1 Normal
(kPa) Diffusion distance R
P O 2
9.3 8 6.7 5.3 4 2,7 1.3 0.8 0.8
1.3
10.7
12 8 6.7 5.3 4 3.5

Capillary
Arterial end Supplied (homogeneous) tissue Venous end Internal (Tissue) Respiration, Hypoxia
2 Hypoxemic hypoxia
(kPa)
P O 2 1.3 0
2.1 0
2.7
4
4.6 4.0 2.7 1,9

“Lethal corner”
(after J.Piiper) Plate 5.13
B. Hypoxia
a
0.20 a‘ Arterial P O 2 falls from a to a‘ 1
O 2 fraction (LO 2 /Lblood) 0.10 v‘ v Hypoxemic hypoxia Normal O 2 extraction unchanged (here 0.5)

0
5
P O 2 10 kPa Venous P O 2 in organ falls from v to v‘
a
0.20 Normal Hb concentration decreases 2
O 2 fraction (LO 2 /Lblood) 0.10 v‘ v Anemic hypoxia O 2 -carrying capacity falls from a to a‘
a‘

O 2 extraction unchanged
0
5
P O 2 10 kPa Venous P O 2 in organ falls from v to v‘
a ·
0.20 Perfusion Q decreases 3
O 2 fraction (LO 2 /Lblood) 0.10 v‘ v Stagnant (ischemic) hypoxia ·
Normal
O 2 supply (=Q · [O 2 ] a ) falls
O 2 extraction rises
0
5
P O 2 10 kPa Venous P O 2 in organ falls from v to v‘ 131
Despopoulos, Color Atlas of Physiology © 2003 Thieme
All rights reserved. Usage subject to terms and conditions of license.